A program to reduce teenagers' intake of sugary drinks showed early benefits, but they didn't last, a new study found.
This study, published Friday in the New England Journal of Medicine, randomly assigned 224 overweight or obese teenagers who regularly drank sugary beverages into two groups. One group participated in a year-long intervention program to discourage them from drinking sugary drinks. The other group did not.
Most kids consume sugary drinks at home, so the researchers tried a new strategy. Calorie-free drinks -- such as plain water and artificially sweetened "diet" beverages -- were delivered to the participants' homes every two weeks for a year.
The program also included monthly motivational telephone chats with parents, several check-in visits and messages reminding the teenagers to drink the delivered beverages and not to consume sugary drinks.
After one year, the participants assigned to the intervention program reported drinking virtually no sugary drinks. Overall, those who were part of this group weighed an average of 4 pounds less and gained weight at a slower rate than their peers who continued to consume sugary drinks.
Sugary drinks -- such as sodas, sports or energy drinks, and sweetened coffees and teas -- have been linked to obesity for a decade, said Dr. David Ludwig, the senior author of the study and director of the New Balance Foundation Obesity Prevention Center at Boston Children's Hospital in Massachusetts.
But there hasn't been a large study that has shown the impact of sugary drinks on weight gain until now, he said.
"Our findings suggest that sugar-sweetened beverages can have a high impact on weight," Ludwig said. "Maybe even the highest among the food groups."
But one year after the program ended, the teenagers who were originally part of the program were now drinking some sugary drinks -- although at an amount that was still less compared with their peers in the control group. At this point, both groups showed the same rate of weight gain and change in body fat.
It's no surprise that they would resume drinking sugary drinks after the home delivery of noncaloric drinks stopped, Ludwig said. "Permanent environmental changes are necessary for permanent weight loss."
According to the researchers, one drawback of their study was that they basked the participants to report their caloric intake, which often leads to underestimating food and drink consumption.
Nevertheless, the results of this study add to the growing body of evidence that links sugary drinks to obesity, said Dr. Andrew Racine, the senior vice president and chief medical officer of Montefiore Medical Center in New York City, who was not involved in the study.
That the study found no differences between the two groups after two years was not surprising, Racine said. In similar studies, the benefits of a program usually disappear once the program ends, he said.
According to other successful public health interventions, what would work for reducing the consumption of sugary drinks in is a combination of individual counseling and social policies, Racine said.
Enacting a public health solution for sugary drinks would be a tricky juggling act between government regulation and personal choice, he said.
Racine supports striking the right balance between "making it more difficult to consume beverages that are less healthy and easier to consume beverages that are more healthy."
Drawing on their findings, the researchers recommend making noncaloric beverages more available and providing clear messages to help teens cut back on sugary drinks.
One study author also suggested creating a sugary drink tax that could raise money for obesity prevention.
Racine believes all this is possible.
"Our beliefs and attitudes evolve over time," he said. "The more we learn about this, the easier it'll be to change public policy.
"When you spend time with parents, they have a profound and deep-seated concern about what's healthy for their children," Racine, who is also a pediatrician, said. "So making policy changes in support of our children's health should not be as challenging as people think."
It's important to remember that sugary drinks are not addictive, said Racine, which helps when it comes to cutting back. It's a taste that's not preprogrammed but develops in our kids, he said. "We can develop a taste for other things."
He cited the recently passed New York City ban on large sugary drinks as a step in the right direction. "[We're] setting up a natural experiment to see whether or not it's effective," he said. "It may turn out that after we institute some of the policies that we don't find as great an effect as we anticipated. That's a possibility. But we need to try."
Studies show that sugary drinks are the largest single source of calories in our diet across the United States. The good news is this study is that if teenagers cut back on sugary drinks, they gain less weight. The disheartening news is that much work is still needed to keep kids from downing sugary drinks for the long-term.
This study, along with two related studies published in the same journal, provide a strong case for regulating the intake of sugary drinks in the battle against childhood obesity, said Dr. Sonia Caprio, a professor of pediatrics at the Yale School of Medicine, who was not involved in any of these studies.
"Furthermore, policy decisions about sugar-sweetened beverages should not be considered in isolation," she said. "Other strategies to achieve and maintain normal weight, including increasing physical activity, will be important to stem the obesity epidemic and its effects.
"These three studies suggest that calories from sugar-sweetened beverages do matter," she said. "The time has come to take action."